Method and apparatus for separating biological materials

ABSTRACT

According to various embodiments, a system can be provided to separate undifferentiated cells and/or stromal cells from a whole tissue sample. The whole tissue sample can be any appropriate tissue sample obtained directly from a patient. The tissue sample can be obtained during a selected operating procedure for immediate or quick application or re-application to the patient. Accordingly, autologous cells can be obtained intraoperatively for application to a patient substantially soon after obtaining a whole tissue sample.

FIELD

The present disclosure is directed to a method and apparatus for separating biological materials, and particularly to a system for separating a selected fraction from a multiple-component biological material.

BACKGROUND

This section provides background information that is related to the present disclosure, but that is not necessarily prior art.

Various cellular (or biological) materials can be used to assist a healing or recovery process in a human patient. Selected cell types, such as stromal cells, pluripotent or multipotent stem cells, or fully differentiated cells, can be applied therapeutically to the patient. For example, stem cells can be applied to an affected area of the patient, such as an area that may be damaged due to injury, chemotherapy, or radiation therapy, to assist in healing the area through differentiation of the stem cells and regeneration of the affected cells.

In performing a therapeutic procedure on a human patient using undifferentiated cells, such as stem cells or stromal cells, the undifferentiated cells can be obtained from various sources, including the patient's own anatomy. Accordingly, certain autologous cells can be applied to or injected into various portions of the anatomy of the patient. Generally, a whole tissue or whole blood sample can be obtained from the patient during a first procedure, selected cells can be separated from the whole tissue or blood sample, and the selected, separated cells can be reapplied to or injected into the patient during a subsequent procedure.

SUMMARY

This section provides a general summary of aspects of the invention, and is not a comprehensive description of its full scope or all of its features.

According to various embodiments, a system can be provided to separate undifferentiated cells, including stem cells and/or stromal cells, from a whole tissue or whole blood sample. The sample can be any appropriate tissue or blood sample obtained directly from a patient. The sample can be obtained during a selected operating procedure with the object of separating undifferentiated cells from the sample for immediate or quick application to the patient. Accordingly, autologous undifferentiated cells can be obtained intra-operatively for application to a patient relatively soon after obtaining a whole tissue or whole blood sample.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples are intended for purposes of illustration only and are not intended to define the scope of the claimed invention.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is an elevation view of a separating system;

FIG. 2A is an exploded perspective view of a buoy system of the separating system of FIG. 1;

FIG. 2B is a cross-section view of the buoy system of FIG. 1 in plane 2B-2B;

FIG. 3 is an elevation view of a method of filling the separation system of FIG. 1;

FIG. 4 is a perspective view of a centrifuge system;

FIG. 5A is an elevation view of an operation of the buoy system of the separating system of FIG. 1 shown partially in section;

FIG. 5B is a detail view of an operation of the buoy system, shown in section, of the separating system of FIG. 1;

FIG. 6 is an elevation view of a fractionated whole tissue or whole blood sample in the separation system of FIG. 1; and

FIG. 7 is an environmental view of an application of a selected fraction of the whole tissue or whole blood sample.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

With reference to FIG. 1, a cell separating system 20 is illustrated. The cell separating system 20 can include a container 22 of any appropriate configuration, such as a substantially cylindrical container having a cylindrical outer wall 24 and closed by a substantially circular bottom wall 26 and a substantially circular upper wall or removable cap 28. The container 22 extends along a longitudinal axis A and the top wall 28 and the bottom wall 26 are positioned separate from each other along and substantially perpendicular to the longitudinal axis A. It will be understood, however, that the container 22 can have any appropriate cross-section, such as a polygonal cross-section, a square cross-section, or any other appropriate shape.

The separating system 20 can include a buoy system 30 positionable within the container 22 and able to move generally axially along the longitudinal axis A relative to the bottom wall 26 and the top wall 28. Buoy system 30 can be configured to contact, in a desired, selected manner, an inner wall surface 32 of the wall 24. For example, the buoy system 30 can be configured to frictionally engage the inner wall surface 32 while separating system 20 is in a substantially static state, and yet move axially relatively freely with respect to the container 22 while separating system 20 is being centrifuged, as described further below. According to various embodiments, the container 22 can be formed of a material selected such that wall 24 can flex outwardly and transversely to the longitudinal axis A, under a selected force. For example, as disclosed in U.S. Pat. No. 7,374,678, issued May 20, 2008, incorporated herein by reference, the container 22 can be positioned in a centrifuge and spun so that a large force, generally several times that of gravity, is applied towards the bottom wall 26 of the container 22 so that the wall 24 flexes outwardly and container 22 compresses. In the compressed state, the cylindrical outer wall 24 can expand in diameter such that inner wall surface 32 can move radially away from the buoy system 30. Consequent clearance between buoy system 30 and inner wall surface 32 allows buoy system 30 to move axially within the container 22 and relative to the inner wall surface 32.

The buoy system 30, as discussed in further detail herein, can include or define a separation or collection volume 40 between an upper buoy portion or member 42 and a lower buoy portion or member 44. A withdrawal member or tube 46 can interconnect a withdrawal port 48 with an extraction port 50 associated with the buoy system 30. The withdrawal port 48 can extend through the top wall 28 to an exterior of the container and the extraction port 50 can communicate with and allow access to the collection volume 40 within the buoy 30. The withdrawal port 48 can include a connector, such as a luer connector 52, that can be selectively capped or blocked with a cap or plug 54.

An introduction port 56 can also extend through the top wall or cap 28 and communicate with an interior volume 57 of container 22. Introduction port 56 can also include a luer connector or an internal taper wall 58 that can interconnect with an introduction syringe 60. A cap or plug 62 can be selectively interconnected with the introduction port 56, after a material is introduced into the container 22, to cap or block luer connector 58. Also defined through the top wall or cap 28 can be a second fraction or plasma withdrawal port 64 that can include a luer lock or connector 65 and also be selectively capped or blocked with a cap or plug 66. The second fraction or plasma withdrawal port 64 can be connected with a port or bore defined through the cap 28 to withdraw or remove a material that is positioned within volume 57 between the buoy system 30 and the cap 28 at any selected time, such as after a separation step formed with the separation system 20.

With reference to FIGS. 2A and 2B, the buoy system 30 can include the extraction port 50, the upper buoy portion 42 and the lower buoy portion 44. The upper buoy portion 42 can have legs or arms 70 extending axially from an annular ring or member 72 to contact an upper transverse surface 74 of the lower buoy portion 44. The legs 70 can extend generally parallel with the longitudinal axis A of the container 22. The legs 70 can contact the upper surface 74 to help support the annular ring 72 of the upper buoy portion 42. The legs 70 can be fixed or connected to the upper surface 74 or only contact the upper surface 74 in a non-fixed manner.

The legs 70 can be formed in any appropriate configuration or number, including two legs as illustrated in FIGS. 2A and 2B, four legs, any appropriate number of legs, or any other appropriate structure, shape or configuration. For example, a colonnade can be formed near an outer edge of the first buoy portion 42 and the second buoy portion 44 to assist in holding the two portions 42, 44 apart. Regardless, the legs 70 can support the first buoy portion 42 at a selected distance from the second buoy portion 44. In yet another configuration, legs 70 can be omitted.

The annular member 72 can connect to spokes or extension members 76 extending radially from a central post or tube 78. The spokes 76 extend generally perpendicular to the axis A. The spokes, however, can extend at an angle relative to the central axis A for reduced drag, etc. The tube 78 defines an internal bore 80 that can communicate with a passage or internal bore 82 of the withdrawal port 50 to permit removal of material from the collection volume 40 of the buoy system 30. The central tube 78 includes an external wall 84 that extends axially from radial spokes 76 at a center or middle of the annular ring 72 to contact the lower buoy portion 44.

A connecting or fusion portion 86 of the central post or tube 78 can extend into and be fixed to the lower buoy portion 44 in an internal well or bore 90. The connecting portion 86 of the post 78 can be adhered, molded, fused, snap fitted, press fitted or interference fitted with the second buoy portion 44. The connection portion 86 can hold the first buoy portion 42 to the second buoy portion 44. Accordingly, the central post 78 can also assist legs 70 in holding the annular ring 72 a distance from the lower buoy portion 44 to define the collection volume 40. Alternatively, central post 78 can hold the annular ring 72 spaced from lower buoy portion 44 in the absence of legs 70.

Fins or raised portions 92 can extend upwardly from the surface 74 of the lower buoy portion 44. The fins 92 can include a ridge or notched portion 94. The central post 78 also can be fixed to the fins 92 to assist in fixing or holding the first buoy portion 42 a selected distance from the second buoy portion 44.

Lower buoy portion 44 can include upper surface 74, an annular or exterior wall 102 and a lower surface 45. The upper surface 74 of the lower buoy portion 44 can be conical and angled or inclined downwardly and inwardly from an outer circumferential edge 100 defined by the intersection or connection of the annular or exterior wall 102 and the upper surface 74. In an imaginary plane that includes longitudinal axis B of the central post 78 and that intersects the upper surface 74, axis B and the line of intersection of upper surface 74 subtend an angle α. The angle α can be any appropriate angle such as about 45° to about 90°, preferably about 75°. Alternatively, upper surface 74 can be concavely spherical rather than conical.

The central portion of the lower buoy portion 44 can define a sump or low portion 103 where a volume of material can be collected, as discussed further herein. The sump 103 can assist in forming a pellet of a selected portion of material, such as a cell fraction. The central post 78, which defines an axial bore 80, can also include a through passage that connects bore 80 in communication with an external receiving port 104 defined by outer wall 84 of post 78. The port 104 can be positioned in or at the bottom of the sump 103 to allow withdrawal of the collected material through the tube 78 and, in turn, through extraction port 50, withdrawal tube 46, and the withdraw port 48.

Positioned around the central post or tube 78 can be a valve system 110. The valve system 110 can include a sealing member 112 made of an appropriate material, such as a silicone rubber material. The sealing member 112 can be configured as a disc or washer including a central aperture, such as a round hole 113, to receive and fit around the central tube 78. A holding or valve actuation member 116 can include an upper apertured disc or washer 117 that is similar in surface area to the sealing member 112 and a mounting or holding cylinder or tube 118 that extends downwardly substantially perpendicularly from disc or washer 117. Holding cylinder 118 and washer 117 receive and fit around central tube 78 below sealing member 112. Holding cylinder 118 can also contact and be supported by the ledges 94 of fins 92 above surface 74, thereby leaving a circumferential clearance around tube 78 relative to fins 92 and holding cylinder 118 to provide communication among the wedge shaped spaces between fins 92. Briefly, the sealing member 112 and the disc 117 can form a flapper valve against the first buoy portion 42. The upper disc 117 of holding member 116 can bend to allow the sealing member 112 to move away from the first buoy portion 42, as discussed further herein and illustrated in FIG. 5B. According to various embodiments, the valve actuation member 116 can be fixed relative to the first buoy portion 42 at a central region 116 a. As illustrated in FIG. 5B, at least the tube 118 and the central portion 116 a of the disc 117 of the valve actuation member 116 remain substantially unmoved as a peripheral edge 112 a of the sealing member 112 and a peripheral edge 117 a of the disc 117 move away from the first buoy portion 42.

The height of the holding cylinder 118 can allow it to contact the ledge 94 and support the disc 117 at an appropriate elevation to hold the sealing member 112 against a bottom surface 120 of the annular member 72 when no opening force is acting on the valve portion 110. The spokes 76 can interconnect the annular member 72 with the central tube or post 78 but also form passages 122 (i.e. openings) between the spoke member 76. The passages 122, when opened by the valve system 110, allow material to move from an area above or exterior to the separation buoy system 30 into the collection volume 40.

The valve system 110 can be formed as one piece that includes both the sealing member 112 and the valve actuation member 116. For example, the sealing member 112 can be a flexible material, such as a silicone rubber, spread or applied to the disc 117 of the actuation portion 116. Alternatively, the sealing member 112 can be a separate piece that is fixed to the valve disc 117 with an adhesive or other connecting mechanism. Further, alternatively, the sealing member 112 can be separate from the valve actuation member 116 and only held in place with the biasing force of the valve actuation member 116. In other words, the sealing member 112 can be manufactured separate from the actuation member 116 or assembled together as the valve system 110.

The valve actuation member 116 can be formed of a material that can flex when a force is applied to it, such as a centrifugal force or pressure differential force, as discussed in detail herein. The material selected for the valve actuation member 116 can include acrylic, polycarbonate, and any other appropriate resilient and substantially inert material. The valve actuation member 116 can be formed of a resilient, yet flexible material. Thus, the actuation member 116 can also be referred to as a flexible member and provide a biasing or closing force on the sealing member 112 against the first buoy portion 42. The valve actuation member 116, therefore, can rebound from an open position to bias the valve 110 in the closed position.

The buoy system 30 can be made of any appropriate material and can be made of a material selected according to the biological material to be placed and separated in the separation system 20. The buoy system 30, however, can be made of materials having a mean density in the range of about 1.03 g/ml to about 1.10 g/ml, preferably in the range of about 1.045 g/ml to about 1.07 g/ml. The density or specific gravity of the buoy separation system 30 can be selected to position the collection volume 40 at an area or position within the separation container 20 relative to the material positioned in the separation system 20. The specific gravity of the buoy system 40 can be selected to move to a selected interface of two or more fractions of a separated multiple component material during separation.

For example, the second buoy portion 44 can be made of a single material or multiple materials and the upper buoy portion 42 can also be made of a single material or multiple materials. The density can be selected by selecting appropriate portions of the materials from which each of the members is made. Selecting the density of the material from which each of the elements of buoy system 30 is made, together with selecting the relative volumes, locations and dimensions of the elements, can assist in achieving a selected placement of the buoy system 30 within the material. The materials can also be selected to be substantially non-reactive to the material being separated in the system 20.

With reference to FIGS. 3-7 a method of using the separation system 20 is illustrated. Initially, a whole tissue sample 140 (e.g. bone marrow aspirate, whole blood, a combination of blood and bone marrow) is positioned within the separation system 20 via introduction from the filling syringe 60. The buoy system 30 can be positioned near the bottom wall 26 of the separation container 22 during filling. The buoy system 30 can move during a centrifugation stage, as discussed further herein.

The whole tissue sample 140 positioned in the separation system 20 can be any appropriate whole tissue sample. For example, the whole tissue sample can include whole blood, bone marrow aspirate or a mixture of whole blood and bone marrow aspirate. The whole tissue sample can include that described in U.S. Pat. No. 7,374,678, incorporated herein by reference above. The whole tissue same 140 positioned within the separation system 20, however, can be separated into selected portions or fractions and selected fractions can be withdrawn from the separation system 20.

The separation system 20 can then be positioned in a centrifuge device 150, as illustrated in FIG. 4. The centrifuge device 150 can include a centrifuge member or rotor 152 with separation wells that can hold the separation system 20 and appropriate blanks or other separation systems. The separation centrifuge 150 can include a centrifuge similar to the centrifuge sold by Biomet, Inc. with the GPS® Platelet Separation System. The separation system 20 can be spun in the centrifuge to direct a centrifugal force along the longitudinal axis A of the separation system 20 towards the bottom wall 26. During centrifugation, the materials of a multi-component material can separate based on specific gravity and density of the components. As understood by one skilled in the art, denser materials will move towards the bottom wall of the separation system 20 and lighter materials move towards the top wall 28.

As illustrated in FIGS. 5A and 5B, during centrifugation, as dense materials move towards the bottom wall 26, the buoy system 30 can move towards the top wall 28 of the separation system 20. As the buoy system 30 moves towards the top of the separation container 28, generally in the direction of arrow X, the centrifugation force and the force of a material pressing on the valve system 110 can bend edges, such as outer or peripheral edges 112 a and 117 a of the valve system 110. When the edges or outer portions 112 a, 117 a bend or move away from the under surface 120, the valve is opened or unsealed. The sealing member 112 unseals from or moves to the open position relative to the annular member 72, such as the bottom portion 120 of the annular member 72. As illustrated in FIG. 5A and in detail in 5B, when the edges 112 a, 117 a of the valve system 110 are bent, material can be move in the direction of arrow Y through the voids or passages 122 between the spokes 76 and into the collection volume 40.

Initially, the valve system 110 can be bent by the centrifugal forces and movement of the whole tissue sample 140 towards the collection volume 40. Then the valve 110 can remain in the open position, bent, during centrifugation due to the density difference between the denser flexible material of discs 112 and 117 and the less dense biological material, such as plasma.

Also, as discussed above, the separation container 22 can flex outwardly, allowing the buoy system 30 to move within the container 22 during centrifugation. The buoy system 30, having the selected density or specific gravity, can move within the separation container 22 to a selected interface of appropriate materials or fractions of the whole sample 140 that is being separated by the centrifugal force. Due to the flex of the container 22 a space can form between the buoy system 30 and the interior wall 32. Thus, material can also move in the direction of Y′ around the buoys system 30. The lower buoy portion 44 can include a conical lower surface 45 to assist in movement of the buoy system 30 away from the lower wall 26.

As illustrated in FIG. 6, once centrifugation has slowed sufficiently, or stopped, the valve system 110 can close with the biasing force of the actuation member 116, in the absence of the opening or external force (e.g. the centrifugal force). The buoy system 30, due to its selected density, can allow the collection volume 40 to be positioned at a selected interface within the separated sample 140. The separated whole tissue sample 140 can include at least a first fraction 140 a that can be closest to the top wall 28 of the separation container 22 and a second fraction 140 b that can be within the collection volume 40 of the buoy separation system 30. The second fraction 140 b can flow around the buoy system 30 when the container 22 flexes. The whole sample 140 can also be separated to include a third fraction 140 c that can be closest to the bottom wall 26 of a separation container 22.

After the centrifugation has stopped, the valve system 110 can close or seal the collection volume 40 from the first fraction 140 a. Accordingly, during extraction or removal of the second fraction 140 b within the separation or collection volume 40, the first fraction 140 a will not interfere or mix with the second fraction 140 b. Because the valve system 110 can assist in maintaining a physical separation of the selected fraction or second fraction 140 b from the other fractions, the separated material can be maintained substantially pure and have a high yield.

Once the separation has concluded, an extraction withdraw syringe or system 160 can be used to withdraw the material or selected fraction 140 b from the separation volume 40 via the interconnection of the withdrawal port 48 via the tube 46, the extraction port 50, the central post or tube 78, and the withdrawal hole 104. Once the material is withdrawn from the separation system 20, a user 170, such as a surgeon, can apply the material to a patient 180 in any appropriate manner. For example, the extraction withdrawal syringe 160 can be fitted or interconnected with a needle 182 to allow injection of the selected fraction into the patient 180. The selected fraction 140 b, as discussed above, can include undifferentiated and/or stromal cells that can be applied to the patient 180 for selected purposes, such as tissue re-growth, healing, or other appropriate purposes.

Thus, the separation system 20 can allow for an introduction of autologous cells to the patient 180. The whole tissue sample 140 can be withdrawn from the patient 180 with the delivery syringe 60 during a single operative procedure. The centrifuge system 150 can be positioned in an operating room or near an operating room for appropriately timed separation of the whole tissue sample to allow for extraction withdrawal of the selected fraction 140 b.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or feature of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention. 

What is claimed is:
 1. A separation system to separate a multiple component material into at least two fractions, comprising: a separation container defining a volume within an interior wall, a first end wall, and a second end wall; a buoy separation system in the volume operable to move to a selected interface of the multiple component material when the multiple component material is separated, the buoy separation system including; a first buoy portion having a passage between a first side and a second side of the first buoy portion; a second buoy portion at a selected distance from the second side of the first buoy portion, wherein the selected distance defines a collection volume between the second side of the first buoy portion and the second buoy portion; a third buoy portion extending between the first buoy portion and the second buoy portion; a valve assembly extending from the third buoy portion, the valve assembly has a sealing member the is formed separate and distinct and is moveable relative to a flexible member, wherein the flexible member is positioned between the sealing member and the second buoy portion and holds the sealing member against the first buoy portion to seal the passage in the first buoy portion to separate the collection volume from a volume exterior to the collection volume on the first side of the first buoy portion; wherein the valve assembly is operable to be unsealed from the first buoy portion to allow a selected fraction to move into the collection volume.
 2. A separation system of claim 1, further comprising: a centrifuge system having a centrifuge bucket operable to hold the separation container and spin the separation container around a central axis of the centrifuge bucket and apply a centrifugal force along a longitudinal axis of the separation container.
 3. The separation system of claim 2, further comprising: a withdrawal port extending through the first end wall of the separation container; and a connection tube interconnecting the withdrawal port and the collection volume between the first buoy portion and the second buoy portion to allow withdrawal of the stromal cells when the valve assembly is sealed; wherein the buoy separation system is operable to move relative to the separation container based upon a force imparted on the buoy separation system by the multiple component material when the separation container is centrifuged in the centrifuge system.
 4. The separation system of claim 1, wherein each of the sealing member and the flexible member have an inner wall defining a passage to fit the valve assembly around a central tube extending from the first buoy portion into the collection volume; wherein at least a portion of the flexible member is fixed relative to the first buoy portion.
 5. The separation system of claim 4, further comprising: an extraction port formed through an outer wall of the central tube to allow withdrawal access to the collection volume.
 6. The separation system of claim 5, wherein the second buoy portion has an upper wall that defines a central sump to collect a pellet of stromal cells.
 7. The separation system of claim 4, wherein the flexible member has a peripheral edge spaced a distance outward from the inner wall of the flexible member, wherein the peripheral edge is configured to move to allow the sealing member to unseal from the first buoy portion.
 8. The separation system of claim 7, wherein the flexible member includes a first portion that is cantilevered and flexes relative to a second portion of the flexible member.
 9. The separation system of claim 1, wherein the interior wall of the separation container substantially defines a cylindrical volume; wherein the first buoy portion includes an annular member extending around a central post and a spoke member extending from the central post to the annular member; wherein the spoke and the annular member define the passage; wherein the valve assembly contacts the first side of the first buoy portion substantially adjacent the collection volume to seal the passage through the first buoy portion.
 10. A separation system including a buoy separation system to separate a multiple component material into at least a first fraction, the buoy separation system comprising: a first buoy portion having a passage between a first side and a second side of the first buoy portion; a second buoy portion spaced a selected distance from the second side of the first buoy portion, wherein the selected distance defines a collection volume between the second side of the first buoy portion and the second buoy portion; and a valve assembly having a sealing member and a flexible member, the flexible member having a central portion fixed relative to the first buoy portion and extending a dimension from the central portion to an outer edge great enough to extend substantially the entire selected distance between the first buoy portion and the second buoy portion when at least the central portion is fixed relative to the first buoy portion; wherein the flexible member holds the sealing member against the first buoy portion to seal the passage in the first buoy portion thus maintaining a separation of the collection volume from a volume exterior on the first side of the first buoy portion; wherein the valve assembly is operable to be unsealed from the first buoy portion to allow the first fraction to move into the collection volume.
 11. The separation system of claim 10, further comprising: a separation container having a volume defined by an interior wall, a first end wall, and a second end wall.
 12. The separation system of claim 11, further comprising: a withdraw port extending through the first end wall; an extraction port extending from the first buoy portion; a tube interconnecting the withdraw portion and the extraction portion; and a tube extending from the extraction portion into the collection volume.
 13. The separation system of claim 12, wherein the tube has an exterior wall that, at least in part, fixes the first buoy portion relative to the second buoy portion the selected distance to define the collection volume between the first buoy portion and the second buoy portion; wherein a first end of the tube extends to the first buoy portion and a second end of the tube extends to a sump defined by an upper wall of the second buoy portion.
 14. The separation system of claim 12, wherein the upper wall of the second buoy portion is formed at an angle relative to an axis of the tube; wherein the angle is about 45 degrees to about 90 degrees.
 15. The separation system of claim 10, wherein the flexible member includes a first disc portion extending radially from a central hub portion, wherein the central hub portion extends substantially the entire selected distance; wherein the sealing member is an annular member operable to be pressed against the first buoy portion by the flexible member.
 16. A separation system including a buoy separation system to separate a multiple component material into at least a first fraction, the buoy separation system comprising: a first buoy portion having a passage between a first side and a second side of the first buoy portion; a second buoy portion positioned at a selected distance from the second side of the first buoy portion, wherein the selected distance defines a collection volume between the second side of the first buoy portion and the second buoy portion; a third buoy portion extending between the first buoy portion and the second buoy portion; and a valve assembly having a sealing member distinct and separate from a flexible member; wherein the flexible member is between the sealing member and the second buoy portion and contacts the sealing member to engage the sealing member against the first buoy portion to seal the passage in the first buoy portion thus maintaining a separation of the collection volume from a volume exterior on the first side of the first buoy portion; wherein the valve assembly is operable to be unsealed from the first buoy portion.
 17. The separation system of claim 16, wherein the sealing member is substantially coextensive and directly contacts the flexible member.
 18. The separation system of claim 16, further comprising: a separation container having a volume defined by an interior wall, a first end wall, and a second end wall; wherein the first buoy portion, the second buoy portion, the third buoy portion, and the valve assembly are configured to be placed within the separation container to assist with separating a material also placed within the separation container.
 19. The separation system of claim 16, wherein the flexible member has a dimension great enough to extend the entire selected distance when contacting the second buoy portion.
 20. The separation system of claim 19, wherein the flexible member includes a first disc portion extending radially from the third buoy portion, wherein the third buoy portion extends substantially the entire selected distance; wherein the sealing member and the flexible member are both annular members, where the sealing member is pressed against the first buoy portion by the flexible member.
 21. The separation system of claim 20, wherein the flexible member applies a force between the second buoy portion and the sealing member to seal the passage of the first buoy portion.
 22. The separation system of claim 7, wherein the valve assembly further includes a holding cylinder to position the flexible member to contact the sealing member.
 23. The separation system of claim 1, wherein the valve assembly further includes a holding cylinder to position the flexible member in contact with the sealing member and to engage a holding portion that is extending from the second buoy portion wherein the holding portion forms a clearance between the holding cylinder and the second buoy portion.
 24. The separation system of claim 1, further comprising: a leg extending between the first buoy portion and the second buoy portion.
 25. The separation system of claim 10, further comprising: a fin extending from the second buoy portion, wherein a clearance between the valve assembly and the second buoy member is formed by contact of the valve assembly with the fin. 